The government's bid to replace carbon trading with its Direct Action plan could produce a double-dissolution election, sending Mr Shorten into a campaign well before the scheduled election in 2016.

He today said he would not comment on detailed policy positions until he had consulted his front bench, to be elected by Caucus tomorrow. He will allocated port folios later in the week.

But Greens leader Christine Milne made clear in a congratulatory tweet to Mr Shorten what she thought Labor should do: "Look forward to working with you to maintain price on carbon.''

He also referred to regional development and small business as elements in a ``positive framework of ideas''.

Mr Shorten, who was first elected to Parliament in 2007, is the second Labor leader in 17 years to have never served in Opposition. Like Kim Beazley in 1996, his first experience on the non-government benches will be as party leader.

But in those six years he first worked for the removal of incumbent Labor Prime Minister Kevin Rudd and then his success Julia Gillard.

"I know, that the time I have been in Parliament, the decisions I've made have been in what I view to be in the best interests of Australia, and the best interests of the Labor Party'' he said.

"No one who serves for a long period in politics and seeks to demonstration the qualities of leadership can avoid answering hard questions. There's no doubt that Labor has been in some difficult times while it was in government.

"But what people will have with me is someone who will always try to work out what is in the best interest of the nation first, and in the best interests of Labor.''

Mr Albanese gave his full support and loyalty to Mr Shorten and to expanding reforms in ALP processes.

The party is now more united and more cohesive, said Mr Albanese, with power taken off the factional bosses.

And, he said, membership wants more power.

``This has not been the end point of the democratisation of the Labor Party. This is just the beginning,'' Mr Albanese told reporters.

Bill Shorten today became federal Labor leader after a surge of support from MPs shut out the people's choice of Anthony Albanese.

Mr Shorten's 55 votes from 86 ALP members of Parliament were more critical to the result that the 18,000 votes for Mr Albanese from rank and file party members.

It was the first time in the history of the Commonwealth the ALP had combined the votes of Caucus and rank and file members - 50 per cent each - to choose a leader.

Mr Shorten will take Labor into the next election scheduled for 2016 unless 60 per cent of his parliamentary colleagues move for his removal under a new system to stabilise the leadership after the turmoil of the Kevin Rudd and Julia Gillard years.

Mr Shorten's vote came to 52.02 per cent of the combined ballots.

Tomorrow Caucus will vote on a shadow ministry and former Health Minister Tanya Plibersek is expected to become Mr Shorten's deputy.

The new leader will have to allocate port folios and it is possible the dynamics within the federal ALP will move from NSW to Mr Shorten's home state of Victoria where he is a leading member of the right. His job has been made easier by former Prime Minister Kevin Rudd's decision not to stand for a front bench slot.

But his chief target will be Prime Minister Tony Abbott who has effectively has been without the check of an Opposition during the three weeks of the leadership campaign.

Acting Labor leader Chris Bowen said the 74 per cent turnout to vote by ordinary party members had changed the ALP forever.

"This process is here to stay. This process had its detractors and its knockers, it had its sceptics," said Mr Bowen.

"Some of those have come to me in recent weeks and said, We were wrong. This process is fantastic."

ALP president Jenny McAlister rejected suggestions the closeness of the vote might add to instability and pointed to Prime Minister Abbott's one-vote win to become Leader of the Opposition in 2009.

"It's not the margin that matters. What actually matters is the human decision made by every member of that Caucus and indeed the rest of us in the broader party, to get behind the leader," she said.